The present invention relates generally to amusement machines having rotating reel assemblies, and to coin operated slot machines of the type found in Monte Carlo, Reno and other internationally known gaming resorts.
The steady rise in popularity of gaming resorts in recent decades has created a highly competitive atmosphere in the gambling industry, as resort owners vie for a larger piece of this growing market. In order to attract the greatest number of customers, one factor which is frequently exploited in the marketing plan of a contemporary gaming facility is the psychological attractiveness of a low probability, high payout option in slot machines. This option appeals to a segment of the market which is otherwise not inclined to gamble, but is intrigued by state lotteries and other low risk games which offer the possibility, however unlikely, of achieving instant wealth in return for a minimal wager. It is, therefore, not unusual to see slot machines in major resorts with potential cash jackpots in excess of $100,000 in return for as little as a $.25 bet.
Not surprisingly, legitimate gamblers are not the only ones who have been attracted by the possibility of instant wealth which these machines offer. The growth of jackpots has produced a highly competent and well-equipped cult of slot machine "pirates," whose techniques for tapping jackpots has advanced at a rate which nearly parallels the growing sophistication of slot machine technology. Accordingly, manufacturers of such machines have developed a variety of systems for verifying the accuracy of a reel spinning operation before issuing cash or credit based on the combination of reel positions resulting from that operation.
The most recent generation of error detection systems utilizes a microprocessor or equivalent circuitry to randomly generate one of a series of numbers for each reel which is being spun, each number of the series corresponding to one of the stopping positions of the reel. A plurality of reel sensors cooperates with a code on each reel to determine its instantaneous rotational position as it spins, and stop the reel when it reaches the stopping position designated by the random number. After the reel has stopped, the microprocessor determines whether the sensed reel position matches the random number, and issues an error signal if it does not. While these machines provide limited protection against tampering, their reel monitoring apparatus is unnecessarily complex and prone to failure, increasing manufacturing cost and down time. Furthermore, the error detection systems in such machines may be circumvented by professionals using state of the art equipment and techniques.
An example of such presently available slot machines may be seen in U.S. Pat. No. 4,421,310 to Williams, which discloses a reel monitoring apparatus utilizing two optic sensors for each reel to monitor the reel's rotational position and determine when its stopping solenoid should be fired. The alignment of these two sensors and maintenance of their mechanical and electrical integrity requires regular inspection and repair, resulting in an undesirable amount of machine down time. Other reel monitoring apparatus, as seen in U.S. Pat. No. 4,238,127 to Lucero, et al., provide five sensors for each reel, assigning a five bit digital code to each of thirty-two reel stopping positions so as to identify each position by a unique address. Such systems require a relatively high degree of maintenance, create complex data input and output requirements, and are generally expensive to design and manufacture due to the large number of parts, connections and processing steps needed to handle the multiplicity of control signals for each reel.
A further drawback to these machines results from their use of an error detection system which computes the intended stopping position of each reel at the start of a game, and then monitors the reel spinning operation to assure compliance with that computed position. Since it is known in advance where the reels of the machine will stop, it is possible to tap this source of data and change the intended stopping positions of the reels, so that the machines will think a legitimate jackpot has occurred when the reels stop at the altered stopping positions.